Al-Malabeh, Ahmad, and Stephan Kempe. “Origin of Iron Ore Nuggets (‘Bohnerze’) through Weathering of Basalt As Documented by Pebbles from the Herbstlabyrinth, Breitscheid-Germany”. Acta Carsologica 34, no. 2 (April 6, 2016). Accessed May 3, 2024. https://ojs.zrc-sazu.si/carsologica/article/view/271.